1. Field of the Invention
The present invention relates to a fuel injector control system for an cylinder injection type internal combustion engine for controlling fuel injectors provided for supplying fuel to individual engine cylinders.
2. Description of Related Art
Generally, in a conventional sequential type multi-point fuel injection control system for an internal combustion engine of a cylinder injection (direct fuel injection) type known heretofore, a variety of information concerning the engine operating state is obtained with the aid of various sensors provided peripherally in association with the engine, wherein fuel injectors provided independently for the individual cylinders, respectively, of the internal combustion engine are electrically and electronically controlled on the basis of the above-mentioned information so that each of the fuel injectors is opened and closed at predetermined timings for predetermined time periods by means of an associated one of injector driving circuits that are provided separately and independently on a cylinder-by-cylinder basis.
In the conventional fuel injector control system, not only for the cylinder injection type gasoline engine but also for the Diesel engine, the injector driving circuit is provided for each of the fuel injectors mounted on the individual engine cylinders, respectively, as typified by the sequential type multi-point fuel injector control system mentioned above.
In a typical one of the fuel injector control systems such as disclosed in Japanese Patent Publication No. 26701/1995 as a sixth embodiment shown in FIG. 7 of the drawings accompanying the specification of the above application, one of the ends of all the injector coils V.sub.1 to V.sub.N are connected in common to a high-voltage generating unit 10 and a constant current circuit unit 30, while the other ends of the injector coils V.sub.1 to V.sub.N are connected to current supply control transistors .tau..sub.1 to .tau..sub.3 provided for the individual engine cylinders, respectively, for controlling individually the injector coils V.sub.1 to V.sub.N independently from one another.
In the conventional fuel injector control system known heretofore, a driving circuit is provided for each of the individual fuel injectors independent of one another in order to cope with such possibility that the electric control of the individual fuel injectors may be performed abnormally due to overlap of the driving period between the plural fuel injectors. Consequently, the conventional fuel injector control system suffers a problem that the fuel injector control system becomes expensive and complicated because of need for providing the driving circuit for each of the fuel injectors provided for the engine cylinders, respectively.